Surgical repair of damaged soft tissue is a procedure that is being carried out with increasing frequency. The most common method for repair of soft tissue damage at or near bone insertion sites involves the approximation of the damaged soft tissue to the insertion site, generally via suture. The suture is then affixed to the insertion site using bone tunnels or a fixation device, e.g., an anchor, which is engaged with the bone. Alternatively, a suture anchor can be first engaged with bone at the soft tissue insertion site and the affixed suture is subsequently used to approximate and secure the damaged soft tissue.
Fixation devices as have been utilized in the past provide certain capabilities. For instance, U.S. Pat. No. 7,329,272 to Burkhart, et al. discloses an interference plug having an outer diameter that is substantially constant and defines a series of ribs and grooves. The device can be utilized to position a graft near a pilot hole and engage within the pilot hole tensioned suture that is attached to the graft. U.S. Pat. No. 7,322,978 to West, Jr. discloses a bone anchor that includes suture attachment sites and continuous threads that extend around the anchor body configured to engage both cortical and cancellous bone tissue. U.S. Pat. No. 6,508,830 to Steiner discloses a suture anchor that includes a cylindrical body portion with an inwardly tapered distal end and a screw thread extending along the body. The device also includes parallel longitudinal grooves cut into the cylindrical body and a transverse suture cavity. In terms of methods, U.S. Pat. No. 5,601,557 to Hayhurst, discloses a method of anchoring and manipulating tissue that includes forming a hole in bone, attaching suture to a member (e.g. an anchor) and securing suture such that the member is lodged into the bone hole and the soft tissue is secured against the bone.
While the above provide improvements in the art, problems still remain. For instance, devices that can provide a high pressure interface with bone, such as through inclusion of sharp ridges or edges, can provide resistance to pull out. However, these devices require special features and knot tying so as to receive suture and to shuttle through and approximate damaged soft tissue to the insertion site. In addition, any direct contact at these high pressure interfaces with soft tissue or an approximation device (e.g., suture) can result in damage, for instance fraying of suture that can compromise the repair. Finally, the above devices and methods are limited to use with suture, and thus cannot be adapted for use with evolving tissue repair constructs such as a surgical mesh or cellular scaffold.
On the other hand, fixation devices that can directly fixate soft tissue within a bone tunnel or slot typically exhibit rounded, atraumatic edges or ridges, usually including insertion with a screw configuration, that are designed to reduce tissue damage. For instance, U.S. Pat. No. 6,099,530 to Simonian, et al. discloses a soft tissue fixation device that includes four channels and four securing members. The four channels include ribs with rounded edges that aid in securing soft tissue in the channels. The four securing members can include a set of wedges oriented toward the distal end of the device that provide an interference fit between the securing members and the wall of the bone tunnel. U.S. Pat. No. 6,562,044 to Cooper describes a multi-component device that includes a first portion including spikes for engaging a graft in a bone tunnel and a second portion, an interference screw having threads, that can be threaded into the bone hole to engage the inner surface of the first portion and an edge of the bone hole to secure the device and the graft in the bone tunnel. These devices rely primarily on compression and friction between the device, the tissue, and the inner bone wall to resist pull out, which is less mechanically desirable than devices that include the direct mechanical interface obtained with devices that include sharper, higher pressure anchoring means. In addition, fixation devices such as those disclosed by Cooper that utilize threaded screw configurations are prone to motion that can cause the soft tissue graft or stump to twist and move from the original placement point.
What are needed in the art are fixation devices that can provide improved mechanical repair of soft tissue injuries and are adaptable to interface with a range of tissue repair constructs and techniques (e.g. tendon stump, suture, and surgical mesh). What are also needed in the art are fixation devices that can provide for both mechanical repair and tissue augmentation in a single step procedure.